1. Field of the Invention
The present invention relates to a gateway system, and more particularly, to a gateway system having automatic dispatch function.
2. Description of the Related Art
A gateway is a network node connecting two different network systems by transforming the format of frames for network packets or the protocol of a network system to ensure the network packets can be safely dispatched to another network system. Because such kind of technology involves many difficult protocol transformations, gateways are among the most complicated and high-end devices in network transmission applications.
Controller area network (CAN) is a network protocol and bus standard, and allows frame communication between subnodes without a host computer. The CAN is initially applied to motor vehicles, and the aforementioned subnodes typically include an engine controller, an air bag, a tire-pressure detector, a brake system, an audio/video system, a window controller and a rear-mirror adjuster. However, with the widespread development of network systems, the CAN is gradually being applied to a range of other, non-automotive fields.
FIG. 1 shows a conventional gateway system applied to the CAN. The gateway system 100 includes a main processor 110, a first transceiver module 120 and a second transceiver module 130. The main processor 110 is connected to the first transceiver module 120 and the second transceiver module 130. The first transceiver module 120 is connected to a first network system 140. The second transceiver module 130 is connected to a second network system 150. In operating the gateway system 100, the first transceiver module 120 receives the frame on a bus of the first network system 140, and then the main processor 110 determines whether it has to instruct the second transceiver module 130 to dispatch the frame to the second network system 150. Because every frame on the bus of the first network system 140 has to be determined by the main processor 110, such operation consumes a lot of computation resources of the main processor 110 and thus a high-performance processor is needed to perform the computation. As a result, the cost of the system is high.
Additionally, the communication protocol of the CAN requires that some subnodes need to report their status regularly. For example, the engine controller and the tire-pressure detector need to regularly report whether the entire operation is normal. Therefore, the gateway system 100 relies on the main processor 110 to dispatch data including the above-mentioned frames regularly, which increases the burden upon the main processor 110.
In short, there is an important need for a design of a gateway system capable of automatically dispatching frames so as to reduce the burden upon the main processor.